Electrically heated tool



Feb- 24, 1942- l.. N. HAMPTON ETAL ELECTRICALLY HEATED TDOL 2Sheets-Sheet l ./v. HAMPTON /NVENTORSAH SHANGLE Filed Feb. 8, 1940 J"52. @M23 mi( A T TORNEY Feb. 24, 1942. l.. N. HAMPTON ETAL ELECTRICALLYHEATED TOOL 2 Sheets-Sheet 2 Filed Feb. 8, 1940 .LM HAMPTON /NVENTORSHSHANGLE wv n uw A .n

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A T TORNE V Patented Feb. 24, 1942 ELCTRICALLY HEATED TOOL Leon N.Hampton, New York, N. Y., and Amos ll. Shangle, Roselle, N. J.,assignors to Bell Tdephone laboratories, Incorporated, New York, N. Y.,a corporation of New York Application February 8, 1940, Serial No.317,798 1 (Cl. B19-26) Claims.

This invention relates to electrically heated tools and moreparticularly to electrically heated soldering coppers and the like.

The object of the invention is to provide an electrically heatedsoldering copper which will be simple in construction, cheap inmanufacture, durable and highly efficient in operation.

A feature of the invention resides in the provision of a tubular supporthaving means at one end for receiving a bushing having a heating elementwith a heat applying tip engaging the bushing in end to end contactrelation with the heating element.

Another feature is the welding of a piece of iron to the heat applyingtip to serve as its working surface.

Another feature resides in the provision of key members passingtangentially through the tubular support and the bushing for securingthe latter to the support.

Another feature resides in forming the tubular support with a portionregistering with the contour of the bushing at its front end to serve asa guard for a conical portion in the bushing forming the bearing pointof the heat transferring tip.

Another feature resides in the provision of means for insulatinglysupporting lead-out conductors in the tubular support while a splicingblock in the support serves for securing the ends of lead-out conductorsto corresponding wires in a cable, and a clip which engages the tubularsupport and a terminal in the block connects with a third wire of thecable for connecting the tubular support to ground.

In the drawings which illustrate one embodiment of the invention:

Fig. 1 is an assembly view;

Fig. 2 is a longitudinal sectional view slightly enlarged showing anumber of operating parts with portions cut away:

Fig. 3 is a cross-sectional view taken on line 3 3 of Fig. 2;

Fig. 4 is a cross-sectional view taken on line 4-4 of Fig. 2;

Hg. 5 is a longitudinal sectional view showing the handle removed fromthe tubular support; and

Fig. 6 is a longitudinal sectional view of a splicing block used forsecuring the ends of the lead-in wires.

Referring to the drawings, a tubular support showninFigs. 1,2and ismadeofsteel alloy containing substantially 18 per cent nickel and istics andwhich is virtually non-scaling at the temperatures at which solderingcoppers commonly operate. 'I'his tubular support has a cylindricalportion 20, a portion 2| of square crosssection and an enlargedcylindrical portion 22, the latter being provided for receiving abushing 24 of copper calorized to prevent oxidation and scaling.

Bushing 24 has its front end rounded and is secured in the enlargedportion 22 of the tubular support by a plurality of olf-center disposedpins 25 and 26 made of steel alloy containing substantially 18 percentchromium and 8 per cent nickel which permits of freedom, and compensatesfor diierential expansion Without introducing noticeable looseness. Thisis important because the copper temperature may change as much as 1000in a few minutes, and as mate-m rial with substantial'. diiferentcoefcients of expansion must be assembled at this point, the pins passthrough perforations in the wall of the tubular support and the bushing,the front end of the tubular support being afterward spun over therounded portion of the bushing for protecting the interiorly machinedconical portion 21 and the screw-threaded portion 21X provided forreceiving the similarly machined end of a heat-transferring element TE.The heattransferring element 'IE is preferably made of a copper part CP,Fig. 2, calorized on its entire surface so as to prevent oxidation andscaling and a pure iron tip IT. The use of a pure iron tip which may be,for example, welded to the copper part CP or electrodeposited on the tipof the copper is for the purpose of increasing the effectiveness of thepart in retaining tinning over that of copper which. is generally used.

The bushing 24'is provided with a reduced portion RP to form incooperation with the interior of the tubular support a circular air pathwhich provides an increasing separation to the handle end where theseparation is the greatest. The heating unit as shown in Figs. 2 and 5is made of a diameter to t into the bushing 24.

The conductors 31 and 38 which connect the heating unit 40 to the cableCA are held in parallel relation to each other in the t' bular supportby a plurality of coaxially disposed ceramic bushings 42 and 43 and apile-up of Bakeite washers 44 adjacent the inner end of a splicng block45 best seen in Figs. 2, 5 and 6 of molded insulating material on whichthe wires 46 and 41 of the three-conductor cord CA are interwoven andelectrically connected to the adjacent ends of poessing low thermalconductivity cnaracterconductors 31 and 38 as shown in Fig. 6, while thethird or grounding conductor 4l of cable CA connects with a bronzeterminal 49 embedded in the splicing block I5 in turn engaged by thestraight portion of a clip member 5l having a curved portion resilientlyengaging the outer periphery of the cylindrical portion 2l ofthe tubularsupport, the straight portion of clip member 5I passing through the wallof the tubular support and a slot SL in the splicing block II so as tohold the splicing block in the support against a pulling force appliedto the. cord CA, thus preventing the breaking of electrical connectionsbetween the wires 4t and 41 and conductors 31 and 38 connecting withthereslstance wire of the heating unit Il. A sleeve 5I which is made ofphenol plastic material is iltted over the reduced portion of splicingblock 4l to serve as a guard for the connecting ends of conductors 31and 38, the ends of lead-in wires Il and 41 and also of the end ofterminal Il with the grounding wire 48 of the cord CA. A handle 52 alsomade of molded insulating material such as phenol plastic is providedwith a screw-threaded ring 5I, Figs. 2 and 5, embedded therein forengaging a screw-threaded portionl SP at the end` of the tubular supportfor securing the handle 52, on such a support against the conicalportion of a disc 54 welded to this support so as to hold the front endof the handle 52 in concentric relation to the tubular support whileforming a guard for this portion of the handle against the heatconducted to this portion of the support. The enlarged end of the handleis provided for protection of the hand against burning by accidentallyslipping on the heated portion of the copper and prevents accidentscaused by the copper falling out of the holder. The handle I2 whenplaced on the portion 2l of the tubular support and securely screwedagainst the disc 54 welded to this support provides an annular air spacebetween the handle and portion 2l and acts as a buffer for the handlewhen the soldering copper is conical portion and said threaded portionin end to end contacting relation with the adjacent end of saidheatingelement. a pair of parallelly disposed pins passing tangentially throughsaid tubular support and said bushing for securing the latter to saidsupport. said support having its end spun over the end of said bushingto serve as a guard for the conical portion in said bushing, and a pieceof iron welded to said heat-applying tip to serve as the working endthereof.

2. An electric soldering iron, comprising a tubular support having anenlarged portion at one end, a bushing mounted in position concentric tothe enlarged portion of said support, an electric heatingelement in saidbushing, a heat-applying tipconnectedtosaidbushinginendtoendrelationwith said element, and a pair of parallelly disposed pinseachengagingsaidsupportattwo -points and said bushing at one point for securing withtwo wires of a three-conductor cable and said terminal with the thirdwire of the cable for connecting said support to ground.

4. A soldering copper comprising a bushing having a rounded end, meansfor securing said bushing into said support. the end of said supportbeing spun over the rounded end of said bushing to serve as a guardtherefor, a heat-transferring element having a screw-threaded portionand a conical portion ,registering with similar portions formed in saidbushing, saidbushng having a reduced portion cooperating with saidsupport to form a circular air path for heat insulating said supportfrom said bushing, a heating element in said bushing, conductorsconnected with said element, a plurality of insulating members forholding said conductors in parallel spaced relation to each other insaid support, a splicing insulating block having a portion fitted insaid support and engaged by said conductors, lead-in wires attached tosaid splicing block and connecting with said conductors, a terminalembedded in said block, another lead-in wire extending through anopening in said block for connection with said terminal, a resilientclip member having a portion contacting with said terminal and a portionengaging said support, a disc carried by said support, a handle securedto said support in abutting relation to said disc, and a sleeve fittedover said splicing block to serve as a guard for the connecting ends ofsaid conductors and said lead-in wires.

5. An electric soldering copper comprising a tubular support, a bushinghaving an enlarged portion fitted with a press fit adjustment in one endof said support with the edge of the support turned in over the end ofsaid bushing, a plurality of parallelly disposed pins passingtangentially through openings in said support and said bushing forsecuring the latter to said support, an electric heating element fittedin said bushing, a heat transferring element having a copper portion andan iron portion, the copper portion having a calorised coating andengaging said heating element in end to end relation. the iron portionbeing welded to said copper portion to form the working end of saidheat-transferring element.

LEON N. HAMPTON. AMOB H. SHANGLE.

